Hydrophobic Surface Induced Biosorption and Microbial Ex Situ Remediation of Oil-Contaminated Sites

It studied the geological properties and contamination characteristics of soil from contaminated sites of typical chromate plants in western plateau of China. The results indicated that in the shallow part of 0-4m, it was mainly loess-like soil and in the depth of 4-18m, it was mainly gravels and pebbles. The soil had better permeability and ex-situ washing treatment is recommended. The soil was severely contaminated and the concentration of chrome (Ⅵ) was as high as 16,000mg/kg. Based on the analysis, it developed a two-stage demonstration project of countercurrent ex-situ washing plus chemical stabilization with daily capacity of 20m3 soil and a demonstration project of chemical reduction and precipitation plus advanced treatment of filter bed with daily capacity of 200m3 wastewater. After treatment, the concentration of chrome (Ⅵ) in soil was less than 100mg/kg and that in water was reduced to below 0.05mg/L from 1,000mg/L, which can meet the requirements of third-grade groundwater quality standard.

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A Remediation Study of Soils Contaminated by Chlorinated Hydrocarbons with Mechanical Soil Aeration

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.878.751 ◽

2014 ◽

Vol 878 ◽

pp. 751-759

Author(s):

Yi Shi ◽

Fa Sheng Li ◽

Xiao Ming Du ◽

Zhu Xu ◽

Yan Ma ◽

...

Keyword(s):

Molecular Weight ◽

Vapor Pressure ◽

Low Cost ◽

Ex Situ ◽

Contaminated Sites ◽

Similar Concentration ◽

Soil Aeration ◽

Long Period ◽

Volatile Organic ◽

Lower Vapor Pressure

Mechanical soil aeration is an effective and low cost ex-situ remediation technique suitable for large areas of volatile organic contaminated sites. To understand the effectiveness of the remediation technique, the current study remediated an abandoned industry site for a typical chlor-alkali chemical using this technology. The results showed that the technology is effective in the remediation of volatile organic compounds with a pass percentage greater than 90%. The results also showed that a lower vapor pressure or higher molecular weight with the similar concentration of pollution resulted in higher residual concentrations, which need increasing agitation frequency or machine power to promote the volatilization of pollutants. In addition, we found that the more pollution or water or organic matters (more than 1%) contained, the higher concentration of residual. These type of soils should be remediated not only by physical agitations but also by other strengthen measures and long period. The present study aims to promote the remediation of contaminated sites, especially large areas contaminated by volatile contaminants.

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Mercury (Hg) Contaminated Sites in Kazakhstan: Review of Current Cases and Site Remediation Responses

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17238936 ◽

2020 ◽

Vol 17 (23) ◽

pp. 8936

Author(s):

Mert Guney ◽

Zhanel Akimzhanova ◽

Aiganym Kumisbek ◽

Kamila Beisova ◽

Symbat Kismelyeva ◽

...

Keyword(s):

Local Population ◽

Soil Washing ◽

Field Investigation ◽

Anthropogenic Sources ◽

Ex Situ ◽

Contaminated Sites ◽

Site Remediation ◽

Plant Site ◽

Northern Regions ◽

Surrounding Areas

Mercury (Hg) emissions from anthropogenic sources pose a global problem. In Central Asia, Kazakhstan’s central and northern regions are among the most severely Hg-contaminated territories. This is due to two former acetaldehyde (in Temirtau) and chlor-alkali (in Pavlodar) plants, discharges from which during the second half of the 20th century were estimated over 2000 tons of elemental Hg. However, the exact quantities of Hg released through atmospheric emissions to the environment, controlled discharges to the nearby aquatic systems, leakages in the cell plant, and contaminated sludge are still unknown. The present review is the initiation of a comprehensive field investigation study on the current state of these contaminated sites. It aims to provide a critical review of published literature on Hg in soils, sediments, water, and biota of the impacted ecosystems (Nura and Irtysh rivers, and Lake Balkyldak and their surrounding areas). It furthermore compares these contamination episodes with selected similar international cases as well as reviews and recommends demercuration efforts. The findings indicate that the contamination around the acetaldehyde plant site was significant and mainly localized with the majority of Hg deposited in topsoils and riverbanks within 25 km from the discharge point. In the chlor-alkali plant site, Lake Balkyldak in North Kazakhstan is the most seriously contaminated receptor. The local population of both regions might still be exposed to Hg due to fish consumption illegally caught from local rivers and reservoirs. Since the present field data is limited mainly to investigations conducted before 2010 and given the persisting contamination and nature of Hg, a recent up-to-date environmental assessment for both sites is highly needed, particularly around formerly detected hotspots. Due to incomplete site remediation efforts, recommendations given by several researchers for the territories of the former chlor-alkali and acetaldehyde plant site include ex-situ soil washing, soil pulping with gravitational separation, ultrasound and transgenic algae for sediments, and electrokinetic recovery for the former and removal and/or confinement of contaminated silt deposits and soils for the latter. However, their efficiency first needs to be validated. Findings and lessons from these sites will be useful not only on the local scale but also are valuable resources for the assessment and management of similar contaminated sites around the globe.

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Production and Application of Biosurfactant Produced by Bacillus licheniformis Ali5 in Enhanced Oil Recovery and Motor Oil Removal from Contaminated Sand

Molecules ◽

10.3390/molecules24244448 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4448 ◽

Cited By ~ 3

Author(s):

Nawazish Ali ◽

Fenghuan Wang ◽

Baocai Xu ◽

Bushra Safdar ◽

Asad Ullah ◽

...

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Packed Column ◽

Hydrophobic Surface ◽

Ex Situ ◽

Wettability Alteration ◽

Motor Oil ◽

Oil Saturation ◽

Ionization Time ◽

Optimized Conditions

The present study describes the production of biosurfactant from isolate B. licheniformis Ali5. Seven different, previously-reported minimal media were screened for biosurfactant production, and two selected media were further optimized for carbon source. Further, various fermentation conditions such as (pH 2–12, temperature 20–50 °C, agitation speed 100–300 rpm, NaCl (0–30 g·L−1) were investigated. The partially purified biosurfactant was characterized by Fourier transform infrared spectroscopy (FTIR) and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS) and found a lipopeptide mixture, similar to lichenysin-A. Biosurfactant reduced surface tension from 72.0 to 26.21 ± 0.3 and interfacial tension by 0.26 ± 0.1 mN·m−1 respectively, biosurfactant yield under optimized conditions was 1 g·L−1, with critical micelle concentration (CMC) of 21 mg·L−1 with high emulsification activity of (E24) 66.4 ± 1.4% against crude oil. Biosurfactant was found to be stable over extreme conditions. It also altered the wettability of hydrophobic surface by changing the contact angle from 49.76° to 16.97°. Biosurfactant efficiently removed (70-79%) motor oil from sand, with an efficiency of more than 2 fold as compared without biosurfactant (36–38%). It gave 32% additional oil recovery over residual oil saturation upon application to a sand-packed column. These results are indicative of potential application of biosurfactant in wettability alteration and ex-situ microbial enhanced oil recovery.

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An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010648x ◽

1988 ◽

Vol 46 ◽

pp. 884-885

Author(s):

D. Loretto ◽

J. M. Gibson ◽

S. M. Yalisove ◽

R. T. Tung

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Defect Density ◽

High Vacuum ◽

Ultra High Vacuum ◽

Ex Situ ◽

Metal Base ◽

In Situ Experiments ◽

Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

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The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150046 ◽

1993 ◽

Vol 51 ◽

pp. 842-843

Author(s):

K. Barmak

Keyword(s):

Thin Film ◽

Thin Films ◽

Phase Transformations ◽

Analytical Electron Microscopy ◽

Ex Situ ◽

Multilayer Thin Films ◽

Absolute Concentration ◽

Analytical Electron ◽

Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

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Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154287 ◽

1989 ◽

Vol 47 ◽

pp. 462-463

Author(s):

D. Loretto ◽

J. M. Gibson ◽

S. M. Yalisove

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Diffraction ◽

High Vacuum ◽

High Energy ◽

Energy Electron ◽

Ultra High Vacuum ◽

Ex Situ ◽

Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

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Interfacial properties of GaSb/InAs superlattices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149969 ◽

1993 ◽

Vol 51 ◽

pp. 826-827

Author(s):

M. E. Twigg ◽

B. R. Bennett ◽

J. R. Waterman ◽

J. L. Davis ◽

B. V. Shanabrook ◽

...

Keyword(s):

Gaas Substrate ◽

Molecular Beam ◽

Infrared Detector ◽

Interfacial Properties ◽

Ex Situ ◽

X Ray Diffraction ◽

Absorption Coefficients ◽

X Ray ◽

Short Period ◽

High Optical Absorption

Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an extensive set of GaSb/InAs superlattices grown on an GaSb buffer, which, in turn had been grown on a (100) GaAs substrate. Through appropriate shutter sequences, the interfaces were directed to assume either an InSb-like or GaAs-like character. These superlattices were then studied with a variety of ex-situ probes such as x-ray diffraction and Raman spectroscopy. These probes confirmed that, indeed, predominantly InSb-like and GaAs-like interfaces had been achieved.

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